(1) Field of the Invention
This invention relates to resin compositions that include one or more high Dk materials in along with a base resin wherein the high Dk material(s) has a dielectric constant is greater than the dielectric constant of the cured base resin. This invention also relates to prepregs and laminates having a homogeneous dielectric constant across the prepreg or laminate cross sections that are made with the inventive resin compositions.
(2) Description of the Art
Prepregs and copper clad laminates are planar materials that are routinely used in the manufacture of printed circuit boards. Prepregs and laminates are typically composite structures that include a reinforcing material such as woven glass, non-woven glass, paper, or other fibrous and non-fibrous materials and a polymeric resin that is used as a matrix material—a material that is applied to or used to impregnate the reinforcing material
With operating frequencies of electronic devices ever increasing, the dielectric properties of the prepregs and laminates are becoming more important to carefully control. One problem with current prepregs and laminates is that the dielectric properties of the reinforcing materials and the matrix materials are very different. When very high speed signals are transmitted through structures such as printed circuit boards built using such metal clad laminates, the signal experiences skew and a difference in speed as the signal propagates over anisotropic regions. This problem is further compounded when a different signal is run and in a worst-case scenario, the difference in propagation speed over long lines leads to major signal integrity problems and in some cases to total signal disappearance. This problem has become a major concern for electronic device designers especially with onboard frequencies moving to 14 GHz and beyond to transmit over 100 Gigabits/second over four channels in which the skew is expected to be a major design challenge.